This KCNA practice question tests your understanding of kubernetes fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which THREE of the following are true about Kubernetes labels and selectors?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set-based selectors support operators like 'In' and 'NotIn'
Option B is correct because Kubernetes set-based selectors support operators like 'In', 'NotIn', 'Exists', and 'DoesNotExist', allowing more flexible matching than equality-based selectors. This is defined in the Kubernetes API specification for label selectors, enabling complex filtering of resources.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Labels are encrypted at rest by default
Why it's wrong here
Labels are not encrypted; they are stored in plaintext in etcd unless encryption is configured.
✓
Set-based selectors support operators like 'In' and 'NotIn'
Why this is correct
Set-based selectors support 'In', 'NotIn', 'Exists', and 'DoesNotExist'.
Related concept
Read the scenario before looking for a memorised answer.
✓
Selectors can be used by Services to identify which pods to route traffic to
Why this is correct
Services use label selectors to determine the pod endpoints.
Related concept
Read the scenario before looking for a memorised answer.
✗
Labels are immutable after creation
Why it's wrong here
Labels can be modified using kubectl label.
✓
Labels can be used to organize and select subsets of objects
Why this is correct
Labels are key-value pairs used to organize and select objects.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that labels are immutable like certain other Kubernetes fields, but labels are explicitly designed to be mutable for dynamic resource management.
Detailed technical explanation
How to think about this question
Under the hood, labels are key-value pairs stored in the metadata section of a Kubernetes object's JSON/YAML manifest, and selectors are evaluated by the API server using a filter mechanism that supports both equality-based (e.g., '=' or '!=') and set-based expressions. In real-world scenarios, set-based selectors are critical for advanced scheduling with nodeAffinity or for Services routing traffic to pods with multiple label combinations, such as 'environment in (prod, staging)'.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the KCNA exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set-based selectors support operators like 'In' and 'NotIn' — Option B is correct because Kubernetes set-based selectors support operators like 'In', 'NotIn', 'Exists', and 'DoesNotExist', allowing more flexible matching than equality-based selectors. This is defined in the Kubernetes API specification for label selectors, enabling complex filtering of resources.
What should I do if I get this KCNA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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